Electromagnetic switch.



P. H. Z!MMEB. ELECTROMAGNETIC SWITCH.

APPLICATION H LED LUNEG. I913. 1,271,001. Patsntad July 2,1918.

UNITED sTATns rare. co, or MILWAUKEE, WISCONSIN,

a CORPORATION or Wisconsin.

ELECTROMAGNETIC SWTTCH.

Specification of Letters Patent.

Patented Jody 2, iii'lltio Application filed June a, 1913. Serial No. 772,088.

To afl'whom it may concern:

Be'it known that IPPAUL H. ZIMMER, a-

citiz-en of the United-States, residing at Milwaukee, in the county of Milwaukee and State of Vvisconsin, have invented new and useful Improvements in Electromagnetic Switches, of which the following is a full, clear, concise, and exact descriptiom refe'rence being had to the accompanying draw- 14} ir g formingapart of -this specification.

his invention relates to electromagnetic switches. I

It relates particularly to switches which are adapted to hold open'when the current in their operating windings is high and to close when the current decreases to apredetermined value. n

One of the objects of the inventionis to provide an electromagnetic switch with improved means for positively looking it in open position when the current through its operating winding is above a critical value.

Another object is to provide an electro magnetic switch having a single winding which closes the switch or positively locksthe' same against closure according to the degree of energization of the winding.

Another object is to provide an improved electromagnetic switch in which the means than the one illustrated may be devised which embody the invention and which come within the scope of the appended claims. In the drawing, Figure 1 is a front elevation of the device, and, i

Fig. 2 is a side elevation thereof, par-' tially in section.

The switch shown comprises'contacts i and 2, which in practice may be of any preferred type. ihe contact 2 is'stationarily mounted the same being supported by an arm or bracket 8 fixed to a supporting panel 4. v The-contact l is mounted upon an arm 5 fulcrumed at 6 to a bracket f7 carried by pivoted plate 8. The plate 8 is fulcrumed' on a pin 9 supported by and between two parallel arms or brackets 10 fixed to the supporting panel 4. A hub spring 12 provides a resilient connection between the arm 5 and the plate 8 which permits the contact 1 to yield with respect to the contact :2- when the plate Sis moved inwardly.

The switch is adapted tobe actuated by an electromagnetic winding 13 having a core 14 and an inverted L-shaped magnet frame d5 fixed to the panel 4. The plate 8 forms the armature of the magnet-.13 and is drawn inwardly to move the contacts 1 and 2 into engagement when saidmagnet is energized. F or a purpose hereinafterset forth the plate 8'is formed in two sections a and b, suitably secured together as by rivets 16. The section a is of magnetic material and of 'suiiicient size to bridgethe core 14- and the frame 15 of the magnet 13 while the section 6 is of noI 1 .magnetic material, such as brass. Likewise, for a purpose hereinafter set forth, the arms or brackets lO supporting the plate 8 are of non-magnetic material, suchas brass:

Thus the magnetic flux for attracting the plate 8 will pass from the core 1.4 through the frame 15 to the plate 8 and thence to the opposite end of the core 14, or in the reverse direction through these parts.

The frame 15, is, however, provided with a downward extension 19 forming a part of second magnetic path for controlling the loclcout means which I shall now describe. As illustrated, the look-out means comprises a latching lever .20 fulcrumed upon a in 21 supported by and between downwardly extending lugs 23 on the arms or brackets 10. vThe outer end of the latch extends through an opening 24 in the lower end of the section of plate 8 and has hook portion 25 adapted to latch on a rolicr 26 sifiiported in the opening 2 of plate 8 by a pin 27. The latching lever 20 is provided at its outer end with a weighted portion 28 biasing said. lever int-o latching engagement with the roller. A coil s ring 29, connect ed between the pin 2'? on the plate 8 and the fixed pin zl biases the switch arm to open. position, in which position the lever 20 automatically latches with the roller Thus the switch is automatically locked out whenever, it returns to full open position. The switch, however, has a limited inward play when in' locked position for a purpose here inafter set forth.

v i For tripping the latching lever to permit the switch to close there is provided atripping member 30 fulcrumed to the pivot of the plate 8 and cooperating with a tail piece 31 on the lever 20. The tripping member 30 is biased in a direction to trip the latch 20 by a coil spring 32 connected at one end to said member and at its opposite end adjustably connected, by a suitable device 33,

to a fixed bracket 34. The member re sists the tension of the spring 32 when the switch is in open position, 'by engagement therewith of a! lug on the plateS. More- 32 draws the member 30 downwardly, trip ping the latching lever 20 and leaving the switch free to close.

It will thus be seen that while the latch 20 always moves to locking position when the switch opens, the switch is, nevertheless, free to close if the tripping member 30 is left free to be drawn downwardly bythe spring 32. If, however, the tripping member 30 is held against operation the latching lever 20 will efiectively lock the switch in open position and only release the same upon release of the tripping member.

As will now be explained, the tripping member 30 is under the control of the magnet 13. It is formed of magnetic material and when the switch is opened is moved into engagement with the downward extension 19 of the magnet frame. It thus cooperates with the extension 19 to form the second magnetic circuit above mentioned. This second magnetic circuit is provided to seal the member 30 to the extension. 19 of the magnet frame to hold the member 30 against the action of the spring 32 and thereby retain the switch in open position. As will be obvious, however, the magnetic reluctance of this second circuit will be much greater than the reluctance of .the first circuit, including the magnetic portion a of the armature plate 8, and accordingly will receive a correspondingly low percentage of the total magnetic flux. Hence by proper proportion and adjustment of-parts the second magnetic circuit may be rendered inefiective to hold the member 30 except when the cur rent through the winding 13 exceeds a definite value. However when the member 30 ting the switch to close. As above set forth,

the spring 32 is adjustably connected to the support 34, and accordingly its tension may be readily adjusted to cause the release of the tripping member 30 at different desired values of the current traversing the magnet winding. WVhat I claim as new and desire to secure by Letters Patent is:

1. In combination, a switch, a latch normally in operative position, for automatically locking theswitch open, a tripping member for said latch normally rendering said switch free to close, and an operating magnet for said switch adapted to magnetically hold said tripping member under certain conditions to render said locking means effective. r

2. An electromagnetic switch comprising a switch arm, an electromagnet for actuating the arm, a latch adapted to lock the switch' arm against movement, atripping member adapted when moved to trip said latch, and means whereby movement of the switch arm permits the tripping member to move and release the latch unless the tripping member is held against movement by magnetic flux from said electromagnet.

3. An electromagneticswitch comprising a switch arm, an electromagnet for actuating the same, a latch adaptedto lock the switch arm against movement, a tripping member adapted when in its normal position to per mit the latch to be effective but adapted to move and release the latch, means to cause the tripping member to move and-release the latch as the switch arm is actuated by the electromagnet, and means whereby the tripping member is magnetically held against movement when the electromagnet is energized by a current which isabove a predetermined value.

l. An electromagnetic switch comprising a switch arm, an electromagnet for actuating the same, a latch adapted to lock the switch arm against movement, means Whereby said latch is released when the magnet is energized by a current below a predetermined value and the switch arm is actuated by the electromagnet, said means being magnetically prevented from releasing the latch when the electromagnet is energized by a current above a predetermined value.

5. An electromagnetic switch comprising a switch arm, an electromagnet for -actuating the same, a latch normally held in opagainst movement, and means whereby movement of the switch arm releases the latch when the electromagnet is energized by a current below a predetermined value.

6. An electromagnetic switch comprising a switch arm, an electromagnet for actuating the same, a latch normally held in operative position for locking the switch arm against movement, means whereby movement of the switch arn'i releases said latch when the electromagnet is energized by a current below a predetermined value, said means being magnetically prevented from releasing the latch when the electromagnet is energized by a current above a predetermined value.

7. An electromagnetic switch comprising an armature, an electromagnet for actuating the same, a latch for locking the armature against movement when the electromagnet is energized by a current above a prede: tel-mined value, said latch being normally biased to its operative position, means for releasing the latch when the electromagnet is energized by a current below a predetermined value and the armature is actuated by the electromagnet, said means being magnetically operated upon when the electromagnet is energizedby a current above a predetermined value so that it will not release said latch.

8. A magnetic switch comprising a switch arm, an electromagnet for actuating the same, a latch adapted to lock the switch arm against movement, said latch being weighted so that it is normally in its operative position, tripping means for tripping the latch, said tripping means being permitted to operate when the switch arm is actuated by the electromagnet but arranged to be magnetically held against movement when the electromagnet is energized by a current above a predetermined value.

9. A magnetic switch comprising a switch arm, an electromagnet for actuating the same, a latch adapted to lock the switch arm against movement, said latch being normally biased to its operative position, a tripping member adapted to trip the latch, a spring acting on said tripping member tending to move it and thereby trip the latch, means whereby said switch arm normally prevents movement of the tripping member, said means permitting the tripping member to move and release the latch when the switch arm is actuated by the electromagnet and means whereby said tripping member is magnetically held against movement when the electromagnet is energized by a current above a predetermined value.

In witness whereof I have hereunto subscribed my name in the presence of two witnesses.

- PAUL H. ZIMMER. Witnesses:

FRANK H. HUBBARD, LEONARD A. WATSON. 

